Detergent lubricating composition



United States Patent nice 2,331,810 Patented Apr. 22, 1958 DETERGENTLUBRICATING COMPOSITION Chester E. Wilson, San Pedro, Calif, assignor toUnion Oil Company of California, Los Angeles, (Ialii, a corporation ofCalifornia No Drawing. Application June 23, 1951 Serial NG- 233,235

5 Claims. (Cl. 252-33.4)

This invention'relates to compositions comprising hydrocarbon oil andnon-metallic salts of sulfonic acids. More particularly the inventionrelates to mineral lubricating oils containing hydrocarbon substitutedguanidine and biguanide salts of petroleum sulfonic acids.

It is well known that ordinary mineral lubricating oil .and the like andcause deterioration or corrosion of corrosion-sensitive bearings. Theseeffects are noted in gasoline engines of the automotive type, in dieselengines and particularly in the newer supercharged diesel engines. Ithas been the practice to add various types of compounds to minerallubricating oil to prevent deterioration of the 33 oil, sludging,formation of engine deposits and'corrosion. However, many of thecompounds which have been used in the past to prevent theseobjectionable features of ordinary lubricating oils lead to otherdifiiculties. For eX- ample, metal salts of fatty acids, substitutedfatty acids,

sulfonic acids and the like have been added to mineral lubricating oilto prevent sludging and prevent formation of varnish and lacquer-likedeposits on engine parts. These metal salts are well known in the art asdetergents since the prevention of sludging and formation of enginedeposits has been considered to be due to the detergent action of theadded metal salts. Although the metal salts mentioned appear to impartdetergent characteristics to lubricating oils when used in sufiicientquantity, the metal content of the oil due to the presence of such metalsalts is sometimes increased to an undesirably high degree so thatburning of the oil, which occurs on upper cylinder walls and within thecombustion chamber, leaves metallic deposits in the form of oxides,sulfates, and the like which are objectionable. Such deposits impaireflicient operation of spark plugs in automotive engines andparticularly the efficient operation of valves. Thus it has beenrealized that a highly desirable detergent would be one which has theability to prevent sludging, formation of lacquer-like engine deposits,and the like, and yet one which does not contain metal as a part of itscomposition. Such a non-metal detergent material will be referred toherein as an ashless detergent.

It has now been found that non-metal or ashless c0rnpounds capable ofimparting detergency as well as other desirable characteristics tomineral lubricating oil may be prepared by reacting sulfonic acids witha hydrocarbon substituted guanidine or a hydrocarbon substitutedbiguanide. The resulting substituted guanidine or biguanide sulfonatesare found to impart a high degree of detergency to mineral lubricatingoils and to improve to some degree at least the anti-corrosioncharacteristics of the oil. Moreover, these sulfonates are sufficientlyoilsoluble to be useful as detergents and they do not impart anyobservable undesirable characteristics to lubricating oils.

Thus, it is an object of this invention to produce mineral lubricatingoils having good'detergency and yet not containing metal salts.

Anotherobject is to produce mineral lubricating oils having highdetergency and anti-corrosion characteristics and yet being free frommetal salts or containing relatively small amounts of metal in the formof salts.

It is a more particular object of this invention to produce minerallubricating oils containing relatively small amounts, sufficient toimpart detergency to such mineral oils, of hydrocarbon substitutedguanidine and/or b"- guanide salts of oil-soluble petroleum .sulfonicacids.

A further object is to produce a detergent, anti-corrosive lubricatingoil containing the mentioned substituted guanidine and biguanidesulfonates together with particular anti-corrosion agents whichcooperate with the sulfonates to impart such desirable characteristicsto the oil.

In preparing the lubricating oils of this inventioncontaining theashless detergents, oil-soluble petroleum sulfonic acids or their metalsalts are converted into the guanidine or biguanide salts which latternon-metal salts are dissolved in lubricating oils. The terms guanidineand biguanide are used herein in their generic sense. to

include the various hydrocarbon substituted guanidine s and biguanidesunless otherwise specifically indicated,

In preparing the guanidine or biguanide salts, oil-soluble petroleumsulfonic acids may be neutralized directly with a guanidine or biguanidecompound and the resulting salt added non-metal salts may also beproduced by metathesis using it alkali metal sulfonate, as for example,sodium sulfonate or potassium sulfonate and the hydrochloride orcarbonate of the guanidine or biguanide compound. In such case theproducts of reaction are the non-metallic sulfonate corresponding to theguanidine or biguanide compound employed and alkali metal chloride orcarbonate. The chloride or carbonate may then be removed from thereaction mixture by extraction with water. More specific directions forcarrying out the preparation of these non-metallic salts are given inthe specific ex amples set forth hereinbelow.

Lubricating oils which may be employed in the preparation of thedeter-gent lubricating oils of this invention include substantially alltypes of mineral lubricating oil. The detergent effect is observed inboth the naphthenictype oils, i. e., those having viscosity indicesranging from about 10 to about 65 'or as well as in the paraffinictypelubricating oil having viscosity indices above about 70. Particularlygood .results have been obtained with a solvent-treated parafiinic-typeoil having a viscosity index of about 90. The effect is similarlyobserved in parailinic-type oils having viscosity indices of over suchas 105.

The guanidine and biguanide compounds which may be employed in thepreparation of the corresponding sulfonate salts include the guanidinesand biguanides having 1 to 3 hydrocarbon substituents and preferably 1or 2 hydrocarbon substituents in which the hydrocarbon substituents areselected from the group consisting of alkyl, cycloalkyl, alkylatedcycloalkyl, aryl, aralkyl and alkaryl radicals. It is not necessary thatall of the substituent groups be the same type of hydrocarbon radical.Thus, one substituent may be aryl, and another alkyl, or one may be aryland another cycloalkyl, for example. The preferred hydrocarbonsubstituent, however, is the aryl substituent.- Compounds which may beused in preparing the non-metal sulfonates include mono-, diandtriphenyl guanidine, mono-, diand tri-tolyl guanidine, mono-, diandtri-benzyl guanidine, mono-, diand trihexyl guanidine, mono-, diandtri-lauryl guanidine, mono-, diand tri-oleyl guanidine, mono-, diandtricyclohexyl guanidine, mono-, diand tri-methylcyclohexyl directly tomineral lubrrcating oil. These 1 and tri-tolyl biguanide, mono-,

,for about 3 hours.

average molecular weight in the range of guanidine, mono-, diandtri-phenyl biguanide, mono-, didiand tri-benzyl biguanide, mono-, diandtri-hexyl biguanide, mono-, diand tri-lauryl biguanidi mono-, diandtri-oleyl biguanide, mono-, diand tri-cyclohexyl biguanide, mono-, diandtri-methylcyclohexyl biguanide.

The number of carbon atoms in each hydrocarbon substituent present inthe guanidine or biguanide compounds may vary from about 2 to or more.Generally each hydrocarbon substituent will preferably contain betweenabout 4 and about 18 carbon atoms. The total carbon atom content of allsubstituents will preferably be between about 4 and about 40 carbonatoms. If the can bon atom content is above about 40 the resultingsulfonate generally does not impart to the mineral lubricating oil thedesired degree of detergency. On the other hand where the carbon atomcontent of hydrocarbon substituents of the guanidine or biguanidecompounds is below about 4 the resulting sulfonates may not besufficiently soluble in mineral lubricating oil to produce the desirableoils of this invention.

The various hydrocarbon substituted guanidines and biguanides may beprepared by methods well known in the art. Some of these compounds arecommercially available. General methods of preparation, however, will beindicated. The aromatic substituted biguanide salts, or aryl biguanidesalts, may be prepared by reacting dicyandiamide with an aromatic amineand an equivalent amount of a mineral acid in water at temperaturesbetween about 75 C. and 100 C. Alkyl and cycloalkyl biguanide salts areprepared by reacting alkyl or cycloalkyl amines with dicyandiamide inthe presence of an equivalent amount of copper sulfate and treating theresulting complex copper salt with hydrogen sulfide to give the alkylbiguanide sulfate.

The various alkyl, cycloalkyl and alkylated cycloalkyl guanidine saltsmay be prepared by reacting dicyandiamide with aliphatic, cycloaliphaticand alkylated cycloaliphatic amine salts at temperatures of about 180 C.The aryl guanidines such as phenyl and diphenyl guanidinearecommercially available and others of this class are obtained by reactingguanidine with the desired aryl amine. This method is applicable to thepreparation of all of the various hydrocarbon substituted guanidinesdescribed herein.

Generally any oil-soluble petroleum sultonic acid or its alkali metalsalt may be employed in the preparation of the substituted guanidine andbiguanide detergents of this invention. Thus the ordinary sodiumsulfonate salts of commerce, such as those obtained as a by-product inthe production of white mineral oils,'which salts have an about 400 toabout 500 are found to produce desirable oil-soluble salts with theguanidine and. biguanide compounds disclosed herein. However, improvedsolubility and improved detergent properties are obtained by using theso-called high molecular weight sulfonate salts of commerce havingmolecular weights in the range of 450 to 550 and outstanding resultshave been obtained using sulfouie acids or their alkali metal saltswhich have been prepared by sulfonating bright stocks or other highviscosity mineral oil fractions such as those having viscosities betweenabout 130250 seconds Saybolt Universal at 210 F. Viscosity indices ofthe sulfonation stocks may vary from as low as to 40 to a high as 100 ormore. Preferably the viscosity index of the fraction will be betweenabout and about 100.

Suitable sulfonation stocks which may be used in the preparation ofsulfonic acids which are to be converted to the guanidine or biguanidesalts as described herein include mineral oil fractions havingviscosities between 50 and 250 seconds Saybolt Universal at 210 F.Included are the typical stocks used in the commercial preparation ofoil-soluble sulfonic acids, i. e., stocks having viscosities of 50 toseconds as well as those of higher vis- .4 cosity which appear to givesulfonic acids of even more desirable characteristics. Particularlydesirable sulfonic acids are obtained by sulfonating petroleum fractionshaving viscosities in the range of to as high as 250 seconds SayboltUniversal at 210 F. Particularly preferred sulfonation stocks arefractions of petroleum referred to in the industry as bright stocks"having viscosities of between about 140 and 225 seconds SayboltUniversal at 210 F.

The preferred sulfonic acids will therefore be those acids whose sodiumsalts have average molecular weights of at least about 450, thecorresponding acids having average molecular weights of at least about428. Of these higher molecular weight sulfonic acids or salts thoseproduced from bright stocks as indicated above are particularlypreferred.

In preparing sulfonic acids, the usual methods of sulfonation may beemployed such as those used in the preparation of white mineral oilswherein sulfonic acids are a by-product of the process as well as thoseused in the commercial production of oil concentrates of mahoganysulfonic acids. In the latter case the mineral oil is treated withconcentrated or fuming sulfuric acid, or with some other sulfonatingagent such as chlorosulfonic acid or the like to effect sulfonation ofat least a part of the oil and the sulfonic acids produced by thistreatment are separated from unsulfonated oil or not depending upon theultimate use of the sulfonic acids. Generally the sulfonated oil isneutralized with an alkali hydroxide such as sodium hydroxide and thesodium sulfonates subsequently are converted into the desired sulfonate.In the present use, the sodium sulfonates are converted into the desiredguanidine or biguanide salts as described herein. Methods of sultonationare well known and need not therefore be further described herein exceptas required to point out modifications, and improvements in thesulfonation method which are employed in connection with the sulfonationof the higher viscosity stocks from which the preferred sulfonic acidsof this invention are obtained. Methods of sulfonation which areparticularly applicable to the preparation of the high molecular weightsulfonic acids of this invention are described in detail in the specificexamplespresented herein.

In preparing a typical hydrocarbon substituted guanidine or biguanidesulfonate salt, a bright stock is obtained from Western parafiinic crudeoil by "conventional procedure. A suitable parafiinic crude oil istopped to remove gas oil and lighter fractions leaving a long residuurnwhich is solvent treated, as for example, with a mixed solventcomprising propane and phenol. The raflinate from the solvent-treatmentis dewaxed and subsequently vacuum distilled to remove lower viscositylubricating oil fractions leaving a residual oil which is clarified asby clay treatment. The resulting bright stock is sulfonated by treatmentwith 45% to 50% by weight of 15% fuming sulfuric acid, the contactingbeing eifected at a temperature between about and F., for a period ofabout 15 to about 60 minutes. Preferably this contacting is effected inthe presence of a low molecular weight paraffinic naphtha having aboiling range between about F. and 275 F. To the resulting sulfonatedproduct is added a small amount of water, approximately one-fourthvolume per volume of bright stock employed, and the mixture permitted tosettle. The aqueous phase is separated and the oil phase neutralized bythe addition of aqueous sodium hydroxide'such as 20% aqueous sodiumhydroxide; Following neutralization the reaction mixture is permitted tosettle and the aqueous phase containing inorganic saltsis discarded. Theneutralized product is then evaporated to recover solvent naphtha anddehydrated by heating to approximately 325 F. Following this treatmentthe heated product is clarified by filtration through filter aid or itmay be cooled and diluted with a light petroleum naphtha andsubsequently filtered at ordinary temperatures. In the latter case it isnecessary to remove solvent by topping. The sulfate ash content ofproducts prepared in this 'mannerare usually between about 2.0% and5.0%. Such products are oil solutions of high molecular weight sodiumsulfonates which will contain between about and by weight of sodiumsulfonate.

A typical detergent salt of this invention is prepared rom a sodiumsulfonate concentrate such as the one described above by treating theconcentrate with, for example, phenyl biguanide hydrochloride. In thisreaction the sodium sulfonate present in the oil concentrate isconverted to phenyl biguanide sulfonate. This metathesis reaction ispreferably efiected in an aqueous alcoholic solution. Thus approximatelyequal volumes of the sulfonate concentrate and water, to which is addedapproximately one-fourth volume of isopropanol per volume of water, isreacted with an aqueous solution of approximately 10% excess phenylbiguanide hydrochloride. The mixture is agitated for approximately onehour. At this time sufficient isoprcpanol is added to the mixture tobreak the emulsion which is formed during the mixing and the resultingreaction mixture is permitted to settle. The aqueous phase is discardedand the oil phase is washed with hot water containing the small amountsof phenyl biguanide hydrochloride and finally with hot water. Thewater-washed oil phase is then dehydrated and filtered at approximately325 F. Products obtained in this manner are found to be substantiallyfree from metal ion as indicated by sulfate ash contents of about 0.1%or less. A typical nitrogen content of such a product is 2.4% by weight.

In'preparing the lubricating oils of this invention the oil concentrateof the substituted guanidine or biguanide sulfonate, which sulfonatesmay be prepared in the manner indicated above for phenyl biguanidesulfonate, is added to mineral lubricating oil of the desiredcharacteristics in substantially any proportion. Generally between about5% and about by weight of the oil concentrate of the non-metal sulfonatewill be employed in preparing the final lubricating oil. The finishedoils will generally contain from 0.5 to 10 or 15% by weight of thenon-metal sulfonates.

Although mineral lubricating oils containing the guanidine or biguanidesulfonates described herein have good detergency and improvedanti-corrosion characteristics as compared With the base oil, it isgenerally desirable, where it is essential that the final oil have goodanticorrosion and/or good anti-oxidation characteristics, to incorporatesmall amounts in the order of about 0.1% to 5% by weight of ananti-corrosion and/or anti-oxidation agent which cooperate with thedetergent of this invention to produce an oil having high detergency,high anti-corrosion characteristics, and high oxidation resistance.Desirably the anti-corrosion agent or anti-oxidation agent will be onewhich does not contain metal, however, since the proportion of suchagents is generally low as compared with detergent, it is possible touse metal salts in the supplemental agents without imparting anundesirably high metal content to final lubricating oil.

Anti-corrosion agents and oxidation inhibitors which have been found tocooperate with the detergent of this invention in that they enhance thedetergent effect of the guanidine and biguanide sulfonates and at thesame time greatly improve the anti-corrosion characteristics of the oil,include the sulfurized and phosphosulfurized terpenes and esters such asalkyl esters of such phosphosulfurized terpenes. Such phosphosulfurizedterpenes are prepared by reacting a terpene or mixtures of terpenes withphosphorus pentasulfide, trisulfide or the like at elevatedtemperatures. The resulting product may be used as such or may beesterified with an alcohol such as an aliphatic or cycloaliphaticalcohol and the resulting esterified compound may be employed.

Another class of compounds which may be employed "to reduce corrosion isthe group of compounds commonly referred to as hindered phenols. Suchphenols are those containing hydrocarbon substituents in at least the 2and 4 positions in the ring and the preferred phenols containhydrocarbon substituents in at least the 2, 4 and 6 positions. Typicalof this group of compounds is 2, 6-ditertiary butyl-4-methyl phenol.

Another class of compounds which may be employed to reduce corrosion ofthe lubricating oils of this invention is the group generally referredto as phenol sulfides. These compounds and their method of preparationare shown in U. S. Patent No. 2,139,321 and include the oilsolublehydrocarbon substituted phenol sulfides. This group includes the simplesulfides or thioethers of the alkyl phenols as well as the disulfides.Examples include amyl phenol sulfide, butyl phenol sulfide and the like.

Still another olass of compounds is the class represented by alizarin,quinizarin and anthragallol. This class consists of the substitutedquinones, naphtha quinones and ant-hraquinones.

Another class of compounds having the desired properties is the classrepresented by the alkyl gallates such as particularly lauryl gallate.This class includes the alcohol esters of trihydroxybenzoic acid inaddition to the lauryl compounds. Other derivatives may be employed suchas stearyl gallate, oleyl gallate, propyl gallate, butyl gallate, hexylgallate, octyl gallate and like compounds.

The above compounds which are either anti-corrosion agents oranti-oxidant, but which in either case tend to prevent corrosion ofcorrosion-sensitive bearings in internal combustion engines are all ofthe ashless or nonmetal type. As indicated herein it is within the scopeof this invention to employ metal salts as anti-corrosion agents. Metalsalts which may be employed include the polyvalent metal salts of phenolsulfides and particularly the alkaline earth metal salts of phenolsulfides such as are described in U. S. Patent No. 2,362,289. Typical ofthese salts are calcium salt of tertiary amyl phenol sulfide.

Another class of anti-corrosion agents is the metal thiophosphates suchas those prepared by reacting P 5 with an alcohol or a phenol. Themethod of preparing these salts and salts which may be employed aredisclosed in U. S. Patent No. 2,364,284. The preferred alcohol andphenol are the monohydroxy organic compounds where the organic groupcomprises an alkyl, cycloalkyl, aryl, aralkyl, or alkaryl radical.Metals such as the alkaline earth metals, calcium, strontium, barium andmagnesium, and the polyvalent metals, zinc, nickel, aluminum, and thelike, may be employed in preparing the metal thiophosphates.

Another class of metal compounds which may be employed includes themetal alkyl substituted dithiocarbamates. A particular example which isfound to be of value is the nickel dihexyl dithiocarbamate.

Methods which have been employed to evaluate the lubricatingcompositions of this invention include variousaccelerated engine testsusing standard test engines. These tests have been run on lubricatingoils with and without the addition of the ashless detergents of thisinvention. Tests have been carried out in a single cylinder Caterpillardiesel standard test engine and under two different sets of conditionsin Lauson single cylinder test engines.

In carrying out the Lauson engine test under high temperatureconditions, which test will be referred to herein as the hightemperature Lauson engine test, the engine is operated for a total of 60hours under a load of about 3.5 horsepower with a coolant temperature ofabout 295 F., and an oil temperature of about 280 F. At the end of thetest, the cleanliness of the engine is observed and given a numericaldetergency rating between zero and where 100% indicates a perfectlyclean engine. Thus a detergency rating of 100 would indicate that therewere substantially no lacquer or varnish-like deposits in the engine. Inthis test the corrosivity of the oil being examined is measured bydetermining the loss in weight of corrosion-sensitive bearings of thecopper-lead type after 20, 40 and 60 hours of operation. When it isobserved that corrosion is extremely severe at the or hour examination,indicating that hearing failure might occur during the next 20-hourperiod of operation, the bearings are removed and replaced with babbitthearings in order to complete the 60-hour test.

In carrying out the Lauson engine test under low tem peratureconditions, which test will be referred to herein as the low temperatureLauson engine test, the engine is operated for a total of 72 hours undera load of about 2.4

horsepower with a coolant temperature of 160 F. and an oil temperatureof 150 F. This test is employed to determine the detergency of an oiland the detergency is rated in the manner described above in connectionwith the high temperature Lauson engine test. No attempt is made in thistest to determine corrosivity. The bearings employed are of the babbitttype.

In the Caterpillar engine test made in the single cylinder Caterpillarengine the engine is operated for a period of 120 hours under a load of19.8 horsepower with a coolant temperature of 175 F. and an oiltemperature of about 145 F. At the end of the test the numericaldetergency rating is assigned. The method of rating is similar to thatemployed in the Lauson engine tests and 100% indicates a completelyclean engine.

The following examples will illustrate methods of preparation ofsulfonic acids from high viscosity mineral oil fractions, methods ofpreparation of hydrocarbon substituted guanidine and biguanidesulfonates and will illustrate oils containing various non-metalsulfonates of this invention and their effectiveness in internalcombustion engines.

Example I A bright stock sulfonate was prepared by sulfonatiug aCalifornia bright stock according to the method outlined below. Thebright stock employed was obtained by topping a waxy paraffnicCalifornia crude oil to remove gas oil and lighter fractions to producea long residuum. This residuum was solvent treated in a conventionalmanner with a solvent comprising propane, phenol and a mixture ofcresols and the raffinate from the solvent treatment was dewaxed in aconventional manner. The dewaxed ratfinate was then vacuum distilled toobtain a residuum having a viscosity at 210 F. of approximately 185seconds. This residuum was clay treated and filtered.

The resulting bright stock had a viscosity index of 85 and a viscosity210 F. of 185.

A mixture of 800 grams of the bright stock and 800 ml. of a lightparafi'inic naphtha having a boiling range between about 150 F. and 210F. was vigorously agitated at room temperature and 200 ml. of 15% fumingsulfuric acid was added over a period of approximately five minutes. Thetemperature rose spontaneously to about 120 F. Agitation was continuedfor approximately minutes, at which time 200 ml. of water was added andthe temperature increased to 155 F. The mixture was allowed to settlefor 18 hours. After settling, the aqueous phase was removed and ml. ofisopropanol was added to the oil phase. Neutralization was effected byadding about 100 ml. of 20% aqueous sodium hydroxide solution andagitating the mixture. Following neutralization the batch was permittedto settle for 18 hours and the aqueous phase then discarded. The oilphase was freed of solvents and dehydrated by heating to 325 F. andstripping with natural gas. The resulting product was then filteredthrough a filter aid at about 325 F. to effect clarification.

The product produced as above consists of an oil con centrate of sodiumbright stock sulfonate containing approximately 20% by weight of sodiumsulfonate. It has a sulfate ash of approximately 4.1%.

8 Example II Example I was repeated. However, in this instance ml. ofwater was added to the sulfonation mixture in place of the 200 ml.portion used in Example I. In this case the spent acid separated moreeasily from the oil solution of sulfonic acids and a somewhat largeramount of sodium hydroxide solution was required to effect completeneutralization. Approximately ml. of 20% aqueous sodium hydroxide wasrequired. The product contains approximately 21% by weight of sodiumsulfonate and has a sulfate ash of approximately 4.

Example III An oil concentrate of phenyl biguanide sulfonate wasprepared from the bright stock sulfonate produced in Example I. Amixture of 400 grams of the sodium bright stock sulfonate from ExampleI, 400 ml. of water and 100 ml. of isopropanol was heated and agitatedat 180 F. and a solution consisting of 50 grams (approximately 10%excess) of phenyl biguanide hydrochloride in 700 ml. of hot water wasadded. Agitation was continued for 40 minutes and then 200 m1. ofisopropanol was added. The mixture was allowed to settle for about 15hours. The separated aqueous phase was withdrawn and discarded and theoil phase containing phenyl biguanide sulfonate was washed with 1 literof hot water containing 5 grams of phenyl biguanide hydrochloride. Asmall amount of isopropanol was added to assist in breaking the emulsionwhich formed during the water washing. After settling the aqueous phasewas withdrawn and the oil phase washed with 1 liter of hot water.Following the latter water wash, the oil phase was dehydrated andfiltered through a small amount of filter aid at 325 F. The metathesiswas judged to be essentially complete since the sulfate ash of the finalproduct was 0.01.

The resulting product had a sulfur content of 1.67% and a nitrogencontent of 2.35% and contained approximately 22% of the phenyl biguanidesulfonate.

A lubricating oil was prepared by dissolving 15% of the phenyl biguanidesulfonate oil concentrate in a mineral lubricating oil of SAE 30 gradehaving a viscosity index of 85. This oil which contained approximately3.3% by weight of the additive was evaluated in the high temperatureLauson engine test and for comparison similar tests were made on thebase oil and on the oil containing the phenyl biguanide sulfonatetogether with (1) 0.5% by weight of a commercial ashless anticorrosionagent containing phosphorus and sulfur and being an ester of aphosphosulfurized terpene, (2) 0.5% by Weight of zinc, dicyclohexyl,dithiophosphate, and (3) 1% by weight of lauryl gallate.

The results of these Lauson engine tests are shown in the followingtable:

weight of the commercial phosphosulfurized terpene ester in an SAE 30solvent-treated Western paraffinic lubricating oil. This oil was testedin the Caterpillar test engine and found to have a detergency rating of98% after 120 hours of operation. For comparison a Caterpillar enginetest on the base oil showed a detergency rating of 49% after the sameperiod of operation.

Example IV A phenyl biguanide sulfonate oil concentrate was preparedfrom a commercial petroleum sulfonate having an average molecular weightof about 470. An emulsion was prepared by heating to 180 F. andagitating a mixture of 1,000 grams of the commercial sulfonate(approximately 60% sodium mahogany sulfonate in mineral oil) 2,000 ml.of water and 500 n11. of isopropanol. To this heated emulsion was addeda solution of 300 grams of phenyl biguanide hydrochloride in 4,000 ml.of water heated to about 180 F. and the resulting mixture was agitatedfor 15 minutes. After settling for 16 hours the aqueous phase waswithdrawn and discarded and the oil phase was washed with 4,000 ml. ofhot water containing 30 grams of phenyl biguanide hydrochloride. Aftersettling and removal of the aqueous phase the oil phase was again washedwith 4,000 ml. of hot water. To the resulting water washed product wasadded 1,000 grams of an SAE 20 solvent treated Western paraffinicmineral lubricating oil having a viscosity index of about 85 and themixture was dehydrated by heating to 325 F. and filtered.

The clarified concentrate containing approximately 35% by weight ofphenyl biguanide sulfonate had a nitrogen content of 3.83% and a sulfurcontent of 2.26%.

A mineral lubricating oil prepared by dissolving by weight of the aboveclarified concentrate in a lubricating oil, was tested in a Lausonsingle cylinder test engine under low temperature conditions asdescribed hereinabove and found to have a detergency rating of 93%. Acomparative test on the oil without additives shows the oil to have adetergency of about 57%.

A second lubricating oil was prepared by dissolving 10% of the aboveclarified concentrate and 1% of lauryl gallate in a portion of the sameSAE 30 mineral lubricating oil. This product had a detergency rating of95%.

Example V A concentrate of the phenyl guanidine sulfonate in minerallubricating oil was prepared from the same com mercial sodium mahoganysulfonate employed in Example IV. In this case 2,000 grams or" thecommercial sulfonate, 4,000 ml. of water and 1,000 ml. of isopropanolwas agitated at 180 F. and to this mixture was added 520 grams of phenylguanidine carbonate. Agitation was continued at 180 F. for '1 hour andthe mixture permitted to settle. The aqueous phase was withdrawn anddiscarded and the oil phase was washed with 6,000 ml. of hot water (180F.) containing 100 grams of phenyl guanidine carbonate. This mixture wasagitated for one hour and then allowed to settle. The aqueous phase wasdiscarded and the mixture then washed with 6,000 ml.

of hot water. To the resulting water-washed product was i added 2,000ml. of an SAE 20 solvent-treated par'aflinic Western mineral lubricatingoil and the resulting mixture was dehydrated and filtered at 325 F. Theresulting product contains approximately 30% by weight of phenylguanidine sulfonate. It has a sulfate ash content of 0.07%, sulfurcontent of 2.05%, and a nitrogen content of 2.80%.

A mineral lubricating oil was prepared by dissolving by weight of theabove oil concentrate in a SAE 30 mineral lubricating oil of the typeemployed in Example IV. The resulting oil has good detergency andimproved anti-corrosion characteristics when employed in internalcombustion engines and operates satisfactorily in automotive engines.

Example VI A phenyl guanidine sulfonate was prepared from the sodiumbright stock sulfonate prepared in Example I using the procedure ofExample V. In this case the 10 product consisted of an oil concentratecontaining ap proximately 22% by weight of the phenyl guanidinesulfonate.

A lubricating oil was prepared by dissolving 18% by weight of the oilconcentrate in an SAE 30 solventtreated lubricating oil to produce anoil containing about 4% by Weight of phenyl guanidine bright stocksulfonate. This oil was tested in a Lauson engine under low and hightemperature conditions. The detergency in the low temperature test was97% and in the high temperature test was 78% as compared with detergencyratings of 57% and 40%, respectively, for the base oil in these sametests. Bearing weight losses at 20, 40, and 60 hours were 44 mg., 97 mg,and 161 mg., respectively, in the high temperature test as compared withlosses of 93 mg, 449 mg, and 597 mg. for the base oil.

Example VII On oil concentrate of dixylyl biguanide sulfonate wasprepared following the procedure outlined in Example III using dixylylbiguanide hydrochloride in place of the phenyl compound. The product,when dissolved in a parafiinic mineral lubricating oil to give asulfonate conten of about 8% by weight produces an oil havingexceptional detergency characteristics.

Example VIII An oil concentrate of diphenyl biguanide sulfonate preparedby reacting diphenyl biguanide hydrochloride with sodium bright stocksulfonate as described in Example I when dissolved in an SAE 30naphthenic lubricating oil to give a finished oil containing 2% byweight of diphenyl biguanide sulfonate, is found to operatesatisfactorily in automotive engines.

Example IX An oil concentrate of hexyl guanidine sulfonate is preparedaccording to the procedure described in Example V using hexyl guanidinein place of phenyl guanidine and bright stock sulfonate of Example I inplace of the commercial sulfonate. A lubricating oil containing 25% ofthe above product has good detergency characteristics as indicated by alow temperature Lauson engine test.

Example X An oil concentrate of lauryl guanidine sulfonate, prepared byreacting 2,000 grams of a commercial sodium sulfonate oil concentratewith 480 grams of lauryl guanidine hydrochloride in solution in 4,000ml. of water and 1,000 ml. of isopropyl alcohol and washing the productfree of inorganic salts, when added to mineral lubricating oil inquantities suflicient to impart a sulfonate content of about 5% byweight produces an oil having excellent detergency properties and fairanticorrosion characteristics. The detergency and anticorrosioncharacteristics are both found to be improved by incorporating in theoil approximately 1% by weight of octylphenol sulfide.

Example XI An oil concentrate of trihexyl biguanide bright stocksulfonate prepared by the procedure outlined in Example III when addedto mineral lubricating oil to give an oil containing approximately 6% byweight of the sulfonate produces an oil having good detergency in thelow temperature Lauson engine test.

Example XII Example XI repeated using methylcyclohexyl bigaunide giveslubricating oils comparable with that of Example XI. In this case aparaifinic lubricating oil containing 6.5% of the methylcyclohexylbiguanide sulfonate has excellent detergency in the low temperatureLauson engine test.

The foregoing description and examples of this invention are not to betaken as limiting since variations a 1 1 may be made by those skilled inthe art without departing from the spirit or the scope of the followingclaims.

I claim: a

1. A composition of matter adapted for addition to lubricating oilconsisting essentially of a mineral oil concentrate containing not morethan about 35% of phenyl biguanide oil-soluble petroleum sulfonate,

2. A composition according to claim 1 in which said oil-solublepetroleum sulfonate is a bright stock sulfonate.

3. A mineral lubricating oil having detergent characteristics consistingessentially of a mineral lubricating oil containing small amounts,between about 0.5% and 15% byweight, suflicient to impart detergencycharacteristics to said oil of phenyl biguanide oil-soluble petroleumsulfonate.

4. A lubricating oil according to claim 3 wherein said oil-solublepetroleum sulfonate is a bright stock sulfonate.

5. A lubricating oil according to claim 3 containing also between about0.1% and about 5% by weight of a phosphosulfurized terpene ester.

References Cited in the file of this patent UNITED STATES PATENTS2,320,263 Carlson et a1 May 25, 1943 2,473,112 Short et al June 14, 19492,564,423 Barnum Aug. 14, 1951 2,620,353 Lippincott et al Dec. 2, 19522,660,562 Axe et al Nov. 24, 1953

3. A MINERAL LUBRICATING OIL HAVING DETERGENT CHARACTERISTIC CONSISTINGESSENTIALLY OF A MINERAL LUBRICATING OIL CONTAINING SMAALL AMOUNTS,BETWEEN ABOUT 0.5% AND 15% BY WEIGHT, SUFFICIENT TO IMPART DETERGENCYCHARACTERISTICS TO SAID OIL OF PHENYL BIGUANIDE OIL-SOLUBLE PETROLEUMSULFONATE.